1. Memory II Reconstructive Memory Forgetting

2. Observe this crime scene

3. Memory Biases
Memory is better for meaningful significant features than for details of language or perception
 gist is remembered better than detail

4. What does a penny look like?

5. Reconstructive nature of memory
Memory is often side-effect of comprehension
details can be filled in or reconstructed at retrieval time
Constructive approach to memory:
Memory = actual events + knowledge, experiences, expectations

6. Verbal labels can distort visual memories
Carmichael, Hogan, & Walter (1932):
While some characteristics of a particular drawing are remembered, the
categorization offered by the verbal cue gives some default information that may be used to fill in
when there is not a complete "visual" memory.
Carmichael, Hogan, & Walter (1932)

7. Effect of Expectation on Memory
A simple demonstration experiment
I am going to show you a picture of a graduate student’s office. Just take a look at it for a while

9. Now write down all the things you can remember
Potential responses:
Chairs
Desk
Table
Boxes
Bottle of wine
Picnic basket
Books
Skull
Schema := knowledge of the typical components of an experience.
Brewer & Treyens (1981):
False memories due to ‘office schema’.
Brewer & Treyens (1981): 30% of subjects (falsely) recalled that books were present

10. Misinformation Effect
Memory for event can be influenced by information given after the event
Misinformation: “Did another car pass the red datsun while it was stopped at the stop sign?
Studied scene
Elizabeth Loftus
Reconstructed memory

11. Explaining Misinformation Effect
Three hypotheses
Overwriting
misleading information alters the memory trace
Source confusion / Misattribution
Perhaps the memory of the question is confused with the memory of the visual scene
Misinformation acceptance
Ss. believe the information in the postevent is true because questioner is a person of authority
Lindsay (1990)
Ss. were told that postevent information was misleading
The misinformation acceptance hypothesis predicts that Ss. can now discount this postevent information
However, Ss. still used postevent information
 Source memory confusion of original event and postevent

12. Overwriting Hypothesis seems unlikely
McCloskey and Zaragoza (1985)
See event: yield sign
Receive misinformation, “as the car passed the...”
misleading: “...stop sign?” nonmisleading: “...yield sign?”
Forced choice test: yield sign OR stop sign  35% drop in accuracy for misleading information
yield sign OR no U-turn  no difference in accuracy for misleading information
(both groups much higher than chance)
A memory of the original event is still retained

13. Relevance to Criminal Justice System
most obvious case
crime  study
picture of suspect (mugshot)  misinformation
Lineup  test
Eyewitness may recognize suspect from mugshot, not from crime scene.
Conclusions:
Do not let potential witnesses see suspects.
Interrogate without asking leading questions

14. Traditional Lineup
Identify the person you saw earlier in the slides

15. Issues with lineups
Faulty eyewitness testimony is the single largest factor leading to false convictions (Wells, 1993)
Big problem:
Eyewitnesses often assume perpetrator is in lineup
If others do not resemble the perp the one who comes closest may be picked.

16. Improved Lineup: Sequential Presentation1 2 3 4 5 6 7 8
Research has shown that the sequential lineup leads to better accuracy and lower false alarms. It is now a required procedure in some states
A sequential lineup forces a comparison with memory not others.

17. Accuracy and Confidence
Eyewitness testimony requires accuracy and confidence
“eyewitness testimony is likely to be believed by jurors, especially when it is offered with a high level of confidence” (Loftus, 1979)
That's him! I'm absolutely positive! I'll never forget that face as long as I live!”
Confidence ≠ Accuracy
(Wells & Bradfield,1999; Loftus & Busey)

18. Unbalanced lineups Problem:
If distractors do not resemble the real perp, the one who comes closest may be picked.
Solution:
All distractor items need to fit description given by suspect and be sufficiently diverse
No individual should stand out
However.....lineups also lead to rightful convictions

19. Biased Lineup?
46%
(A)
(B)
(C)
(D)
(E)
(F)
(from Geoff Loftus)

20. Recovery of Lost Memories?
Several lawsuits have relied on eyewitness testimony of repressed memories. These memories were “recovered” by family member or therapist
Claim: repression follows stress, but repressed material can be returned to consciousness with the removal of stress (e.g., Zeller, 1950, 1951; Merrill, 1954)
Problem:
Are these repressed memories or false memories (based on misinformation)?

21. Recovered memory vs. False Memory
How do we know whether repressed memories are accurate? Hard to falsify
In some cases, traumatic information is misremembered or simply “made up”
Loftus has been involved in many cases
Points out problems of
hypnosis
suggestive questioning
dream interpretations
Even if repressed memories exist, they should be subject to normal forgetting and interference processes
Elizabeth Loftus

22. Can false memories be implanted?
You, your mom, and your brother went to Kmart. You were 5 years old. Your mom gave each of you some money to get a blueberry Icecream. You ran ahead to get into the line first, and lost your way in the store. Your mom found you crying to an elderly woman.
Loftus and Pickrell (1995)
can Ss. be made to (incorrectly) remember that they were lost in the mall in their childhood?
Experiment
Experimenter interviews relatives of Ss.
Experimenter then told Ss. of true and false events from their childhood
Example false memory: being lost at a mall at age 5
After that, Ss. rated stories on whether they remembered from childhood
Results:
68% of the true events and
29% of false events “remembered”
Loftus and Pickrell (1995)

23. Can false memories be implanted?
Loftus and Pickrell (1995)
can Ss. be made to (incorrectly) remember that they were lost in the mall in their childhood?
Experiment
Experimenter interviews relatives of Ss.
Experimenter then told Ss. of true and false events from their childhood
Example false memory: being lost at a mall at age 5
After that, Ss. rated stories on whether they remembered from childhood
Results:
68% of the true events and
29% of false events “remembered”
Loftus and Pickrell (1995)

24. False Memory in the Lab SNORE NAP SLUMBER PEACE DROWSY YAWN BLANKET
Deese, Roediger, McDermott paradigm
Study the following words
Recall test ....
Recognition memory test Use ratings 1) sure new 2) probably new 3) probably old 4) sure old
TEST:
SNORE
NAP
SLUMBER
PEACE
DROWSY
YAWN
BLANKET
DOZE
SNOOZE
BED
AWAKE
REST
TIRED
WAKE
DREAM
SLEEP
COFFEE
SNORE
REST

25. Results
Critical lures (“sleep”) are words not presented but similar to studied words. These words are often falsely recalled (sleep: 61% of Ss.)
Recognition memory results
proportion of items classified with confidence levels:
confidence rating
studied items
not studied
unrelated
critical lure
(e.g. “REST”)
(e.g. “COFFEE”)
(e.g. “SLEEP”)

26. Accuracy and Confidence
False memory experiment shows sometimes confidence is high while accuracy is low

27. Forgetting

28. Forgetting Functions
Ebbinghaus (1885/1913): Forgetting over time as indexed by reduced savings.
Most forgetting functions show:
Negative acceleration
Rate of change gets smaller and smaller with delay
Power law of forgetting
Although memory processes are operating at every moment of the day, typically we are not aware of the functioning of memory until attempts to remember are met with failure—that is, when we forget.
Forgetting is the inability to recall or recognize previously encoded information. Although some instances of forgetting are due to poor initial encoding, and others are due to the lack of the right cues at the right time, many instances of forgetting result from postencoding mechanisms.
In his classic work Memory (1885/1964), Hermann Ebbinghaus systematically examined how memory for encoded stimuli and events changes as the retention interval—the time between encoding and retrieval—increases.

29. Reminiscence Bump
Enhanced memory for (episodic and semantic) facts of adolescence & young adulthood.
One explanation for reminiscence bump: encoding is better in periods of rapid change, followed by relative stability. Evidence from those who emigrated to the US after young adulthood indicates reminiscence bump is shifted
Schrauf & Rubin (1998)

30. Is there a purpose of forgetting?
Why (should) we have Bad Memory?
Luria (1975): Shereshevskii’s ‘virtually limitless’ memory
– could not forget irrelevant details
– bad at inductive reasoning (‘filling in the blanks’)
Computational level explanations for forgetting
Anderson & Schooler (1991):
It is efficient for our memory system to make recent and frequent memory more readily accessible

31. Algorithmic level explanations of forgetting
Decay
Memories just fade and disappear (not much evidence for this)
Interference
Memory is still there but we can’t retrieve it
newer memories interfere with older memories  Blocking
Suppression & Repression
 controversial (!)
Ample evidence indicates that many instances of forgetting are caused by interfer­ence. Interference theories hold that if the same cue is bound to a number of repre­sentations, these representations compete during retrieval, resulting in interference. Newer memories interfere with older ones, and older ones with newer ones; and the result is that neither old nor new stimuli or events are perfectly recalled—even though the information is still in memory, we have forgotten because retrieval attempts have failed. (p. 225)

32. Example
You call a friend, but realize you need an older phone number that you have not used for a while. With effort, you recall the correct old phone number
FRIEND
NEW PHONE NUMBER
OLD PHONE
NUMBER

33. Blocking
One explanation: The old number is blocked by the new association
FRIEND
Blocking theories hold that forgotten information still resides in memory but is temporarily blocked by a dominant competing representation
NEW PHONE NUMBER
OLD PHONE
NUMBER

34. Retrieval Induced Forgetting
An alternative explanation for the problem of retrieving the old phone number is that the old memory has been suppressed because the new phone number was retrieved  retrieval induced forgetting
FRIEND
NEW PHONE NUMBER
OLD PHONE
NUMBER
(the old phone number memory has been weakened)

35. Blocking or Suppression?
Blocking would predict that using a new cue would remove blocking effect. Suppression would predict the memory cannot be accessed with a new cue either
FRIEND
OTHER MEMORY CUES
NEW PHONE NUMBER
OLD PHONE
NUMBER

36. Blocking or Suppression?
Anderson & Green show that other memory cues are not effective either and argue for suppression
FRIEND
OTHER MEMORY CUES
NEW PHONE NUMBER
OLD PHONE
NUMBER

37. Inhibitory processes in memory?
Suppression is an example of an inhibitory process
Can we actively inhibit or suppress our memories? How would that work?
Note: many memory researchers do not buy into concept of suppression of memories. More research needs to be done